. >> reporter: rachell deveano was helping kids with autism. her aunt says her boyfriend was planning to propose this christmas eve. kate snow, nbc news, sandy hook, connecticut. >> at that same interfaith service last night in newtown, president obama sounded both sad and exasperated about gun violence. and he said enough is enough. >> we can't tolerate this anymore. these tragedies must end. and to end them, we must change. no single law, no set of laws, can eliminate evil from the world or prevent every senselesses act of violence in our society. but that can't be an excuse for inaction. surely we can do better than this. >> the president said he would use the power of his office to prevent more gun tragedies, and tonight he is being joined by a growing number of prominent voices. tom costello has that part of the story in washington tonight. tom, good evening. >> reporter: hi, brian. it's been a very busy day. the mayor of america's biggest city today urged congress, in fact, challenged congress and the white house to act, and the nra remai